Drainage discovery

If you have cropland near a stream, river or lake, which most Minnesota farmers do, chances are that you’ve taken your share of criticism when those neighboring waters turn murky or slimy or kill aquatic life.

Oct 29, 2010

Drainage discovery

By PAULA MOHR

If you have cropland near a stream, river or lake, which most Minnesota farmers do, chances are that you’ve taken your share of criticism when those neighboring waters turn murky or slimy or kill aquatic life.

Agriculture usually gets the blame when natural resources become tainted. However, more people and programs are taking a broader view and looking at other possible sources of contaminants. They aren’t just making educated guesses either. They are collecting hard data and documenting facts.

Key Points

• First Discovery Farm has results from 2007 to 2009 on city and farm drainage.

• Data show that phosphorus and sediment losses are higher in city stormwater.

• Nitrate drainage is greater from fertilized fields than from stormwater.

That’s what has been happening at Gorans Brothers Farms since 2007. The second-generation farm is owned by Kim Gorans, his father and brother, and uncle and cousins. They raise 45 million pounds of turkey a year and farm 4,000 acres, raising corn and soybeans. As the crow flies, the farm is five miles south of Willmar. Tucked in between the city and their fields is Lake Wakanda, a 1,745-acre lake used for fishing and recreation.

Over the years, the Goranses and their farm neighbors heard complaints about how their businesses were affecting the lake’s water quality.

“We were always hearing that the problem was ‘those turkey farms,’” Kim Gorans says. “There had been some vegetation and fish that died. So a neighbor had some lake water tested. But those were grab samples, and the high numbers didn’t make sense.”

About a decade ago, Gorans attended a meeting where John Moncrief, University of Minnesota Extension soil scientist, presented results from a study that discussed nutrient runoff from liquid manure and commercial fertilizer when applied to frozen crop ground. Gorans also learned of another study at the time, sponsored by Kandiyohi County, which showed that farmland between area lakes was not the cause of nonpoint-source pollution.

“I knew we were doing things right on our farm with incorporating manure, fertilizing based on soil test and using precision farming,” he says. Yet he wanted proof that these practices were protecting the area’s natural resources.

On a trip to St. Paul, Gorans approached Moncrief and asked him if he would be interested in monitoring water quality on his farm and the nearby lake. Moncrief agreed.

Testing water in, water out

With financial assistance from turkey, corn and soybean organizations, the county and U-M, Moncrief and colleagues developed an extensive city and farm water-quality-monitoring project that collects data on nutrient runoff and pathogens, crop yield response, lake chemistry, and sediment loss. The project also is working under the umbrella of the state’s new Discovery Farms program.

Thus far, the project has yielded interesting results: Phosphorus and sediment losses were much higher from city stormwater runoff than farm fields. Nitrate drainage was greater, understandably, from fertilized fields than stormwater. However, an unfertilized control field contained more nitrate in drainage than stormwater.

City-farm impact: John Moncrief (left), University of Minnesota soil scientist, and turkey producer Kim Gorans, Willmar, visit the west lift station, one of five sites where U-M researchers are continually monitoring drainage water flow. Inside the small PVC pipe (on top of the large white pipe) is a lead wire from an area and velocity sensor that is connected to a data logger.